Obesity and type 2 diabetes are two complex disorders with strong genetic backgrounds, and both disorders cause other diseases and increase mortality. FTO is a protein-coding gene located on the long arm of chromosome 16 and linked to type 2 diabetes and obesity. The current study investigated the relationship between the RS16953002 polymorphism gene and type 2 diabetes and obesity in a population from Tehran. The study population included 150 people with type 2 diabetes and 150 healthy individuals. Genotyping was performed by RFLP-PCR. The results indicated the presence of the GG allele in 81% of diabetic patients but in only64% of non-diabetic participants, which shows a statistically significant difference in this regard. Thus, the current study has shown the role of FTO gene polymorphisms in the pathogenesis of people with type 2 diabetes and obesity.